L. Forró szerk.: Miscellanea Zoologica Hungarica 13. 2000 (Budapest, 2000)

Spolwind, R., Schludermann, C. , Schuster, A.; Waidbacher, H.: Comparison of fish and amphibian communities in a floodplain system of the rivers Traisen and Danube westwards of Vienna

Table 4. Cluster analysis (Ward) of stagnant back water types with stable fish coenoses. Split numbers show mesohabitats within one backwater system. Cluster Backwaters Characterising species Type 1.1 46, 7, 35 C. carpio Fish ponds 1.2 28, 5 M. fossils Backwater 3. order 2.1 83, 94 P. fluviatilis, R. rutilus., A. alburnus Backwater 3. order 2.2 62, 89 E. lucius, R. rutilus Backwater 3. order 2.3 92/1 E. lucius, R. rutilus, T. tinea, B. bjoerkna Backwater 3. order 3.1 86, 88, 64 C. a. gibelio, C. carassius, R. rutilus Backwater 3. order 3.2 87,90 P. fluviatilis, G. aculeatus, P. marmoratus, C. auratus gibelio, A. alburnus, A. brama Backwater 3. order 4.1 84, 85 T. tinea, C. carassius, S. erythrophthalmus, E. lucius, R. rutilus, A. alburnus, P. marmoratus, P. fluviatilis, A. brama Backwater 2. order 4.2 70 L. idus, L. cephalus, E. lucius, R. rutilus, A. alburnus, P. marmoratus, P. fluviatilis, A. brama, B. bjoerkna, Backwater 1. order 4.3 98 E. lucius, R. rutilus, A. alburnus, A,, brama, P. fluviatilis, P. marmoratus, T. tinea., S. erythrophthalmus Backwater 2. order The result of the hierarchical cluster analysis of fish data of stagnant backwaters shows a segregation due to typology of habitats and due to their position in the investigated area. Backwaters of third order show mostly low species numbers, eurytopic and limnophilic species dominate. Both species numbers and rate of rheophilic elements increase in more dynamic backwater types (systems of second and first order, cluster 4). Relevant habitats in the Traisen region are rare (Nr. 28 and 5) and show limnophilic fish coenoseses, where M. fossilis is dominant. Habitats with higher species numbers are restricted to the Danube-Traisen region. Flowing Backwaters This separated cluster analysis includes all investigated flowing systems with representative fish coenoses. We distinguished three clusters, cluster one is defined through low species number and eutrophication; cluster 2 and 3 are backwater systems with different human impact. Subclusters 2.2 and 3 show well structured, typical flow water conditions. Clustering flowing water systems shows a segregation between human influenced systems (Nr. 61, 42) with high eutrophication and fluctuating water levels and more natural habitats (mostly cluster 3, Nr. 30) with its significantly higher species numbers. Table 5. Cluster analysis (Ward) of flowing backwater types with stable fish coenoses. Split numbers show mesohabitats within one backwater system. Cluster Backwaters Characterising species Type 1.1 42,61 P. phoxinus, B. barbatula, L. cephalus, P. fluviatilis Low flow section of a small backwaters, highly eutrophicated backwater 2.1 34_3 S. t.f. fario, B. barbus, L. cephalus, P. phoxinus, G. gobio, R. rutilus, C. a. gibelio Human influenced urban backwater section 2.2 48 S. t.f.fario, L. cephalus, P. phoxinus, B. barbatula, G. gobio, Small, shadowed, non affected stream 3 30 S. t. f. fario, 0. mykiss, P. phoxinus, B. barbatula, G. gobio, A, anguilla, P. fluvial Us Heterogeneous non affected flowing system